Memory systems are widely used in information processing systems to store data. Memory systems may be generally classified as solid state memory systems or moving memory systems. Solid state memory systems generally include various types of integrated circuit devices with arrays of memory cells thereon, such as static random access memory (SRAM) and dynamic random access memory (DRAM). Moving memory systems include floppy disk, hard disk and CD-ROM.
In the personal computer industry, multiple integrated circuit memory devices are often packaged together on a printed circuit board or card to form a memory module. Memory modules may be connected to several slots within a computer system.
FIG. 1 is a block diagram which illustrates a dynamic random access memory (DRAM) system and conventional peripheral circuits which control the DRAM system. As shown in FIG. 1, there are four slots designated A, B, C, D. A conventional DRAM controller 20, buffer 30 and write buffer 10 are also included. Memory modules which include DRAMs of the same type are used in each of the four slots A, B, C, D. For example, if extended data output (EDO) DRAMs are used, they are generally used in all four slots. If different DRAM modules, such as fast page (F/P) DRAMs are used, the DRAM controller 20 may not be able to distinguish from one another. Thus, the same operating signal may be sent to each of the modules that are connected to the slots. As such, the DRAM modules with different types may not operate.
Moreover, even if the modules having different types of DRAMs can operate in response to the same output signal which is generated by the DRAM controller 20, the different types of DRAM may not operate in an optimum manner. Thus, the DRAM controller may detect that the modules 40 are reading and writing data, and may thereby determine the amount of memory which the DRAM controller is controlling. However, the controller may not be able to optimize operation for each of the plurality of memory types.